CONCORD, N.C. – NASCAR announced on Tuesday afternoon that a new rules package for most short ovals and road courses will debut next weekend at Phoenix Raceway. 

The aerodynamic rules package will result in a decrease in downforce of around 30%, NASCAR officials have indicated. This will be used at all the tracks where NASCAR had previously announced that "wet weather equipment" would be in use in the event of damp conditions. Those tracks on the NASCAR Cup Series schedule are: The Charlotte Motor Speedway ROVAL, the Chicago Street Course, Circuit of The Americas, Indianapolis Motor Speedway Road Course, Martinsville Speedway, New Hampshire Motor Speedway, North Wilkesboro Speedway, Phoenix Raceway, Richmond Raceway, Sonoma Raceway and Watkins Glen International. 

2023 NASCAR Cup Series schedule

The only short ovals that will not utilize this package are the concrete tracks of Dover Motor Speedway and Bristol Motor Speedway. Both those tracks are also not included in the tracks where "wet weather equipment" could be used if events warrant it. 

The changes for this package will see a two-inch rear spoiler, instead of the current four-inch spoiler as well as the removal of three diffuser strakes, engine panel strakes and trimming the diffuser’s outer fencing. These changes were tested at Phoenix in January. 

Ahead of its debut at Phoenix on Sunday, March 12 (3:30 p.m. ET on FOX, MRN Radio and SiriusXM NASCAR Radio-Channel 90), for the fourth Cup Series race of the season, teams will get a 50-minute practice session on Friday, March 10 starting at 6:35 p.m. ET.